JP7254475B2 - Surface-treated silica particles, dispersions and resin compositions containing the same, and cured products of resin compositions - Google Patents

Description

TECHNICAL FIELD The present invention relates to a surface-treated silica particle, a dispersion containing the same, a resin composition, and a cured product of the resin composition.

Silica particles and silica particle dispersions obtained by dispersing silica particles in a solvent can improve strength, hardness, heat resistance, insulating properties, etc. properties can be improved, it is useful for applications such as adhesive materials, dental materials, optical members, coating materials (for hard coats and anti-glare), and nanocomposite materials. Above all, particularly for hard coat applications, the hard coat is required to have high surface hardness and high scratch resistance.

For example, in Patent Document 1, a modifier having a thiol group and a trifunctional or higher (meth)acrylate monomer are covalently bonded to a thiol group and an acryloyl group and/or a methacryloyl group using an addition reaction to obtain a polyfunctional A hardware having a first step of obtaining a (meth)acrylate monomer-modified modifier and a second step of modifying the polyfunctional (meth)acrylate monomer-modified modifier obtained in the first step to metal oxide fine particles A method for producing a coating resin composition is disclosed.

JP 2011-213989 A

Patent Literature 1 described above describes that the scratch resistance and surface hardness of the hard coat are improved by modifying the metal oxide fine particles with the above-described specific surface modifier. However, as a result of examination by the present inventor, the silica particle-dispersed MIBK solution specifically disclosed in Patent Document 1 is silica particles produced by the water glass method, and the silica particles disclosed in Patent Document 1 are When trying to treat the surface modifier used, the reaction solution after adding the surface modifier gelled, and it was difficult to reproduce the surface-modified silica particles disclosed in Patent Document 1.

Therefore, the present invention is a silica particle surface-treated with a surface-treating agent, and a hard coat containing the surface-treated silica particles can be produced, and the surface-treated silica particles can further increase the scratch resistance of the hard coat. intended to provide

（前記式（Ａ）中、ｎは１～３の整数、ｍは１～１０の整数、Ｘ¹は炭素数１～４のアルコキシ基、Ｒ¹¹は炭素数１～４のアルキル基、Ｒ¹²は下記式（１Ａ）で表される基である。）

（前記式（１Ａ）中、ｐは２～１０の整数であり、Ａ¹は直鎖状、分岐鎖状又は環状の炭素数１～３０の（ｐ＋１）価の炭化水素基又は該炭化水素基のメチレン鎖の一部が－Ｏ－、－ＮＨ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＨ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）Ｏ－に置換された有機連結基であり、Ｒ^a1は独立に水素原子又はメチル基である。）

（前記式（Ｂ）中、ｔは１～３の整数、ｓは１～１０の整数、Ｘ²は炭素数１～４のアルコキシ基、Ｒ²¹は炭素数１～４のアルキル基、Ｒ²²は下記式（１Ｂ）で表される基である。）

（前記式（１Ｂ）中、ｑは２～５の整数、Ｂ¹は直鎖状、分岐鎖状又は環状の炭素数１～１０の（ｑ＋１）価の炭化水素基又は該炭化水素基のメチレン鎖の一部が－Ｏ－、－ＮＨ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＨ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）Ｏ－に置換された有機連結基であり、Ｒ^b1は独立に水素原子又はメチル基である。）
［３］透過型電子顕微鏡で測定した一次粒子径の平均値が５～１００ｎｍである［１］又は［２］に記載の表面処理シリカ粒子。
［４］［１］～［３］のいずれかに記載の表面処理シリカ粒子と溶媒とを含む表面処理シリカ粒子分散体。
［５］［１］～［３］のいずれかに記載の表面処理シリカ粒子と重合性単量体とを含む表面処理シリカ粒子含有樹脂組成物。
［６］［５］に記載の表面処理シリカ粒子含有樹脂組成物の硬化物。 The present invention is as follows.
[1] Silica particles surface-treated with a surface treatment agent,
The surface treatment agent includes (i) a silane coupling agent having a thiol group, a thioMichael addition reaction product of a trifunctional or higher (meth)acrylate monomer, and (ii) a silane coupling agent having an isocyanate group, At least one selected from the group consisting of a bond with a bifunctional or higher (meth)acrylate monomer having one or more hydroxy groups,
The coefficient of variation of the primary particle size measured with a transmission electron microscope is 20% or less,
Surface-treated silica particles having a sphericity of 0.90 or more.
[2] The (i) silane coupling agent having a thiol group and a thioMichael addition reaction product of a trifunctional or higher (meth)acrylate monomer is represented by the following formula (A), and the (ii) isocyanate group is The surface-treated silica particles according to [1], wherein a bond of a silane coupling agent having a silane coupling agent and a bifunctional or more functional (meth)acrylate monomer having one or more hydroxy groups is represented by the following formula (B).

(In formula (A), n is an integer of 1 to 3, m is an integer of 1 to 10, X ¹ is an alkoxy group having 1 to 4 carbon atoms, R ¹¹ is an alkyl group having 1 to 4 carbon atoms, R ¹² is a group represented by the following formula (1A).)

(In the above formula (1A), p is an integer of 2 to 10, and A ¹ is a linear, branched or cyclic (p+1)-valent hydrocarbon group having 1 to 30 carbon atoms or the hydrocarbon group Part of the methylene chain of -O-, -NH-C(=O)-, -C(=O)-NH-, -OC(=O)-, -C(=O)O- a substituted organic linking group, and R ^a1 is independently a hydrogen atom or a methyl group.)

(wherein t is an integer of 1 to 3, s is an integer of 1 to 10, X ² is an alkoxy group having 1 to 4 carbon atoms, R ²¹ is an alkyl group having 1 to 4 carbon atoms, R ²² is a group represented by the following formula (1B).)

(In the formula (1B), q is an integer of 2 to 5, B ¹ is a linear, branched or cyclic (q+1)-valent hydrocarbon group having 1 to 10 carbon atoms or methylene of the hydrocarbon group Part of the chain is substituted with -O-, -NH-C(=O)-, -C(=O)-NH-, -OC(=O)-, -C(=O)O- is an organic linking group, and R ^b1 is independently a hydrogen atom or a methyl group.)
[3] The surface-treated silica particles according to [1] or [2], which have an average primary particle diameter of 5 to 100 nm as measured by a transmission electron microscope.
[4] A surface-treated silica particle dispersion containing the surface-treated silica particles according to any one of [1] to [3] and a solvent.
[5] A resin composition containing surface-treated silica particles, comprising the surface-treated silica particles according to any one of [1] to [3] and a polymerizable monomer.
[6] A cured product of the surface-treated silica particle-containing resin composition of [5].

According to the surface-treated silica particles of the present invention, a cured product of a resin composition containing the surface-treated silica particles can achieve excellent scratch resistance.

According to the study of the present inventors, it is found that the coefficient of variation of the primary particle size and the sphericity of the silica particles after the surface treatment are within a predetermined range while using a specific surface treatment agent as disclosed in Patent Document 1. Furthermore, it was found that a hard coat containing surface-treated silica particles can be produced, and that it is effective in improving the scratch resistance of the hard coat.

The surface-treated silica particles of the present invention have a coefficient of variation of primary particle diameter (hereinafter referred to as TEM diameter) measured by a transmission electron microscope (TEM) of 20% or less. The TEM diameter, for example, may be measured using a transmission electron microscope at a measurement magnification at which the number of silica particles contained in one field of view is about 100 to 300, and the standard deviation of the primary particle diameter is the primary particle diameter. The coefficient of variation of the TEM diameter can be calculated by dividing by the number-based average value. The coefficient of variation of the TEM diameter is 20% or less, preferably 17% or less, more preferably 14% or less, even more preferably 12% or less, and still more preferably 10% or less. Although the lower limit of the coefficient of variation of the TEM diameter is not particularly limited, it may be 5%, for example.

The average value of the primary particle diameter of the surface silica particles measured by TEM is, for example, 5 nm or more, preferably 10 nm or more, more preferably 15 nm or more, and may be 100 nm or less, or 90 nm or less. is preferred, more preferably 50 nm or less, and even more preferably 35 nm or less.

Further, the sphericity of the surface-treated silica particles is 0.90 or more. In the present invention, the sphericity means a value obtained by dividing the short diameter of the surface-treated silica particles by the long diameter. The sphericity may be measured using a transmission electron microscope at a measurement magnification of, for example, about 50 to 100 silica particles included in one field of view, and the number-based arithmetic average value may be calculated. The sphericity is preferably 0.92 or more, more preferably 0.94 or more, and still more preferably 0.95 or more. Although the upper limit of the sphericity is not particularly limited, it is usually about 0.99.

The coefficient of variation of the TEM diameter and the sphericity of the surface-treated silica particles described above are properties peculiar to the silica particles obtained by the method for producing silica particles described later. In addition, since the coefficient of variation of the TEM diameter and the sphericity described above hardly change before and after the surface treatment, the silica particles before the surface treatment also have a coefficient of variation of the primary particle diameter measured by a transmission electron microscope of 20% or less. The sphericity is 0.90 or more. In addition, the silica particles before the surface treatment have a d _BET calculated from the specific surface area by the BET method of 1 nm or more and 100 nm or less, and an average secondary particle diameter d _DLS measured by a dynamic light scattering method, and the d It can also be said that silica particles have a _BET ratio (d _DLS /d _BET ) of 1.2 or less.

The d _BET of the silica particles before surface treatment is preferably 70 nm or less, more preferably 50 nm or less, still more preferably 30 nm or less, particularly preferably 25 nm or less, and may be, for example, 3 nm or more, more preferably 5 nm or more. . The d _BET is an average particle diameter calculated based on the surface area and volume of silica particles, and is an index of the particle diameter of primary particles, excluding the influence of aggregation of silica particles.

In addition, the ratio of d _DLS to d _BET (d _DLS /d _BET ) of the silica particles before surface treatment is preferably 1.15 or less, more preferably 1.1 or less, for example 1 or more, or even 1 0.01 or greater is also acceptable. In the dynamic light scattering method, the particle diameter is measured based on the moving speed of the silica particles in the methanol dispersion when the silica particles are made into a methanol dispersion having a concentration of 1% by mass or more and 15% by mass or less, Since the moving speed of the silica particles in the methanol dispersion correlates with the volume occupied by the silica particles, when the silica particles are aggregated, the particle size of the aggregated silica particles (secondary particles) can be obtained. can be done. Therefore, the degree of aggregation of silica particles can be estimated from the ratio of the DLS diameter d _DLS to the BET diameter d _BET .

The _dDLS of the silica particles before surface treatment is that the silica particles have a particle concentration of 1% by mass or more and 15% by mass or less (preferably 3% by mass or more and 12% by mass or less, more preferably 5% by mass or more and 10% by mass or less). Laser light (preferably wavelength 650 nm) is irradiated to the dispersion dispersed in methanol so as to be, and the autocorrelation function is obtained by the photon correlation method from the temporal fluctuation fluctuation of the scattered light intensity, and the average particle size is obtained by the cumulant method. It can be calculated as (hydrodynamic diameter) and serves as an index of the particle diameter of secondary particles.

The specific surface area of the silica particles before surface treatment is preferably 30 to 1000 m ² /g, more preferably 100 to 700 m ² /g, still more preferably 150 to 500 m ² /g. The specific surface area of the silica particles can be measured by the BET method.

In addition, as will be described later, silica particles are produced by a so-called sol-gel method in which alkoxysilane is hydrolyzed and condensed. alkaline earth metals, etc.) is reduced. For example, the content of impurity metals is preferably less than 5 ppm, more preferably less than 1 ppm in the surface-treated silica particles. Metals as impurities include heavy metals such as Pb and Cr, and radioactive substances such as U and Th. It is preferable that the content of these metals is also reduced. The content of heavy metals is preferably less than 1 ppm, and the content of radioactive substances is preferably less than 0.1 ppb. The metal content as the impurity can be measured using a high-frequency plasma emission spectrometer (Agilent 8800; manufactured by Agilent Technologies, etc.). Specifically, the surface-treated silica particle dispersion was evaporated to dryness, and the obtained powder sample (5 g) was added to and mixed with a mixed solution of hydrofluoric acid and nitric acid. Water is added sequentially to make the total volume 50 mL, which can be used as a measurement sample solution for measurement.

Next, the surface treatment agent will be explained. The surface treatment agent in the present invention includes (i) a thioMichael addition reaction product of a silane coupling agent having a thiol group and a trifunctional or higher (meth)acrylate monomer (hereinafter referred to as surface treatment agent A), and (ii) ) At least one compound selected from the group consisting of a silane coupling agent having an isocyanate group and a bifunctional or higher (meth)acrylate monomer having one or more hydroxy groups (hereinafter referred to as surface treatment agent B). Seeds. Since surface-treating agent A and surface-treating agent B have two or more acryloyl groups or methacryloyl groups, silica particles surface-treated with at least one selected from the group consisting of surface-treating agent A and surface-treating agent B are used. A hard coat containing can improve scratch resistance.

In this specification, (meth)acrylate means acrylate, methacrylate and mixtures thereof, and (meth)acrylic acid means acrylic acid, methacrylic acid and mixtures thereof.

(i) a thiomichael addition reaction product of a silane coupling agent having a thiol group and a trifunctional or higher (meth)acrylate monomer (surface treatment agent A)
In the surface treatment agent A, the thiol group of the silane coupling agent and the (meth)acryloyl group of the (meth)acrylate monomer are covalently bonded by a thio-Michael addition reaction, whereby the silane coupling agent and the (meth) It is a compound in which an acrylate monomer is bound. That is, the surface treatment agent A is a compound in which a monovalent group having two or more (meth)acryloyl groups and a —CH ₂ —CH ₂ —S— bond and a hydrolyzable group are bonded to a silicon atom. It can be said that there is. A group other than the monovalent group and the hydrolyzable group may be bonded to the silicon atom. The hydrolyzable group is, for example, an alkoxy group, preferably an alkoxy group having 1 to 4 carbon atoms. The number of hydrolyzable groups may be 1 or more, preferably 2 or more, and more preferably 3.

A silane coupling agent having a thiol group is a compound in which a monovalent group having a terminal thiol group (—SH) and an alkoxy group are bonded to a silicon atom, and is represented by, for example, the following formula (s1). .

（上記式（ｓ１）中、Ｒ³¹及びＲ³²はそれぞれ独立にフェニル基又は炭素数１～４のアルキル基であり、ａは１～１０の整数であり、ｂは０～２の整数である。）

(In formula (s1) above, R ³¹ and R ³² are each independently a phenyl group or an alkyl group having 1 to 4 carbon atoms, a is an integer of 1 to 10, and b is an integer of 0 to 2. .)

Silane coupling agents having a thiol group include, for example, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylethyldiethoxysilane, 1-mercaptomethylmethyldimethoxysilane. silane, 11-mercaptoundecyltrimethoxysilane, and the like.

Examples of trifunctional or higher (meth)acrylate monomers include compounds in which at least three OH groups of compounds having three or more alcoholic OH groups are ester-bonded to (meth)acrylic acid. Examples of the compound having 3 or more alcoholic OH groups include trihydric or higher alcohols; compounds having 3 or more alcoholic OH groups, which are urethane bond-forming products obtained from polyhydric alcohols and diisocyanates; be done. The trihydric or higher alcohol is preferably, for example, a trihydric to hexahydric alcohol.

Trihydric alcohols include glycerin, 1,2,3-butanetriol, 1,2,4-butanetriol, 2-methyl-1,2,3-propanetriol, 1,2,3-pentanetriol, 1, 2,4-pentanetriol, 1,3,5-pentanetriol, 2,3,4-pentanetriol, 2-methyl-2,3,4-butanetriol, 2-methyl-2,3,4-butanetriol , trimethylolethane, 2,3,4-hexanetriol, 2-ethyl-1,2,3-butanetriol, trimethylolpropane, 4-propyl-3,4,5-heptanetriol, 2,4-dimethyl- 2,3,4-pentanetriol, tris(2-hydroxyethyl) isocyanurate and the like.
Tetrahydric alcohols include erythritol, pentaerythritol, diglycerin, sorbitan and the like.
Pentahydric alcohols include adonitol, arabitol, xylitol, triglycerin and the like.
Hexavalent alcohols include dipentaerythritol, sorbitol, mannitol, iditol, inositol, dulcitol, talose, allose and the like.

Trifunctional or higher (meth)acrylate monomers include glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol triacrylate, and pentaerythritol. tetra(meth)acrylate, dipentaerythritol hepta(meth)acrylate, dipentaerythritol hexa(meth)acrylate and the like.

The surface treatment agent A is preferably represented by the following formula (A).

（前記式（Ａ）中、ｎは１～３の整数、ｍは１～１０の整数、Ｘ¹は炭素数１～４のアルコキシ基、Ｒ¹¹は炭素数１～４のアルキル基、Ｒ¹²は下記式（１Ａ）で表される基である。）

(In formula (A), n is an integer of 1 to 3, m is an integer of 1 to 10, X ¹ is an alkoxy group having 1 to 4 carbon atoms, R ¹¹ is an alkyl group having 1 to 4 carbon atoms, R ¹² is a group represented by the following formula (1A).)

（前記式（１Ａ）中、ｐは２～１０の整数であり、Ａ¹は直鎖状、分岐鎖状又は環状の炭素数１～３０の（ｐ＋１）価の炭化水素基又は該炭化水素基のメチレン鎖の一部が－Ｏ－、－ＮＨ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＨ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）Ｏ－に置換された有機連結基であり、Ｒ^a1は独立に水素原子又はメチル基である。）

(In the above formula (1A), p is an integer of 2 to 10, and A ¹ is a linear, branched or cyclic (p+1)-valent hydrocarbon group having 1 to 30 carbon atoms or the hydrocarbon group Part of the methylene chain of -O-, -NH-C(=O)-, -C(=O)-NH-, -OC(=O)-, -C(=O)O- a substituted organic linking group, and R ^a1 is independently a hydrogen atom or a methyl group.)

X ¹ in formula (A) above is preferably an alkoxy group having 1 to 2 carbon atoms. R ¹¹ is preferably an alkyl group having 1-2 carbon atoms. m is preferably 1 to 5. n is preferably 2 to 3, more preferably 3. More preferably, all of the above preferred requirements for X ¹ , R ¹¹ , m, and n are satisfied at the same time.

The p (meth)acryloyloxymethyl groups in the above formula (1A) may be bonded to one carbon atom in A ¹ , or a plurality of carbon atoms (meth)acryloyloxymethyl groups are bonded to and the total number of (meth)acryloyloxymethyl groups bonded to the -A ¹ - group may be p. p is preferably 2-5. A ¹ is preferably linear or branched, and a linear or branched hydrocarbon group having 1 to 10 carbon atoms or part of the methylene chain of the hydrocarbon group is -O- More preferably, it is a substituted organic linking group. A ¹ is a linear or branched hydrocarbon group having 1 to 10 carbon atoms or an organic linking group in which a part of the methylene chain of the hydrocarbon group is substituted with —O—, and p is 2 to 5 is more preferred.

As the surface treatment agent A, the following compounds are preferred.

R a1 , X ¹ and n in formulas (a1) to (a4 ⁾ above have the same meanings as R ^a1 , X ¹ and n in formula (1A) above.

(ii) a bond of a silane coupling agent having an isocyanate group and a bifunctional or higher (meth)acrylate monomer having one or more hydroxy groups (surface treatment agent B)
In the surface treatment agent B, the isocyanate group of the silane coupling agent reacts with the hydroxy group of the (meth)acrylate monomer to form a urethane bond, whereby the silane coupling agent and the (meth) It is a compound in which an acrylate monomer is bound. That is, surface treatment agent B can also be said to be a compound in which a monovalent group having two or more (meth)acryloyl groups and urethane bonds and a hydrolyzable group are bonded to a silicon atom. A group other than the monovalent group and the hydrolyzable group may be bonded to the silicon atom. The hydrolyzable group is, for example, an alkoxy group, preferably an alkoxy group having 1 to 4 carbon atoms. The number of hydrolyzable groups may be 1 or more, preferably 2 or more, and more preferably 3.

A silane coupling agent having an isocyanate group is a compound in which a monovalent group having an isocyanate group (-N=C=O) at its end and an alkoxy group are bonded to a silicon atom, for example, the following formula (s2) is represented by

（上記式（ｓ２）中、Ｒ⁴¹及びＲ⁴²はそれぞれ独立にフェニル基又は炭素数１～４のアルキル基であり、ｃは１～１０の整数であり、ｄは０～２の整数である。）

(In formula (s2) above, R ⁴¹ and R ⁴² are each independently a phenyl group or an alkyl group having 1 to 4 carbon atoms, c is an integer of 1 to 10, and d is an integer of 0 to 2. .)

A bifunctional or higher (meth)acrylate monomer having one or more hydroxy groups is a compound having three or more alcoholic OH groups, in which two alcoholic OH groups are ester-bonded with (meth)acrylic acid, and at least one Compounds in which alcoholic OH groups remain can be mentioned. Examples of the compound having three or more alcoholic OH groups include those exemplified for the surface treatment agent A, and tri- to hexahydric alcohols are preferred.

Bifunctional or higher (meth)acrylate monomers having one or more hydroxy groups include 2-hydroxy-3-acryloyloxypropyl methacrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and the like. .

The surface treatment agent B is preferably represented by the following formula (B).

（前記式（Ｂ）中、ｔは１～３の整数、ｓは１～１０の整数、Ｘ²は炭素数１～４のアルコキシ基、Ｒ²¹は炭素数１～４のアルキル基、Ｒ²²は下記式（１Ｂ）で表される基である。）

(wherein t is an integer of 1 to 3, s is an integer of 1 to 10, X ² is an alkoxy group having 1 to 4 carbon atoms, R ²¹ is an alkyl group having 1 to 4 carbon atoms, R ²² is a group represented by the following formula (1B).)

（前記式（１Ｂ）中、ｑは２～５の整数、Ｂ¹は直鎖状、分岐鎖状又は環状の炭素数１～１０の（ｑ＋１）価の炭化水素基又は該炭化水素基のメチレン鎖の一部が－Ｏ－、－ＮＨ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＨ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）Ｏ－に置換された有機連結基であり、Ｒ^b1は独立に水素原子又はメチル基である。）

(In the formula (1B), q is an integer of 2 to 5, B ¹ is a linear, branched or cyclic (q+1)-valent hydrocarbon group having 1 to 10 carbon atoms or methylene of the hydrocarbon group Part of the chain is substituted with -O-, -NH-C(=O)-, -C(=O)-NH-, -OC(=O)-, -C(=O)O- is an organic linking group, and R ^b1 is independently a hydrogen atom or a methyl group.)

X ² in formula (B) above is preferably an alkoxy group having 1 to 2 carbon atoms. R ²¹ is preferably an alkyl group having 1-2 carbon atoms. s is preferably 1-5. t is preferably 2 to 3, more preferably 3. More preferably, all of the above preferred requirements for X ² , R ²¹ , s, and t are satisfied at the same time.

The q (meth)acryloyloxymethyl groups in the above formula (1B) may be bonded to one carbon atom in B ¹ , or a plurality of carbon atoms to which the (meth)acryloyloxymethyl groups are bonded. and the total number of (meth)acryloyloxymethyl groups bonded to the -A ¹ - group may be q. q is preferably 2-5. B ¹ is preferably linear or branched, a linear or branched hydrocarbon group having 1 to 10 carbon atoms, or part of the methylene chain of the hydrocarbon group is -O- More preferably, it is a substituted organic linking group. B ¹ is a linear or branched hydrocarbon group having 1 to 10 carbon atoms or an organic linking group in which a part of the methylene chain of the hydrocarbon group is substituted with —O—, and q is 2 to 5 is more preferred.

As the surface treatment agent B, the following compounds are preferred.

R ^b1 , X ² and t in the above formulas (b1) to (b4) are synonymous with R ^b1 , X ² and t in the above formula (1B).

The surface treatment agent is preferably at least one surface treatment agent A, and among the surface treatment agents A, at least one of the surface treatment agents represented by the above formulas (a3) and (a4) is particularly used. is more preferred.

The surface-treated silica particles of the present invention may be further surface-treated with at least one of a silane coupling agent other than the above-described surface treatment agents (A and B), a disilazane compound, and a titanium coupling agent. The surface is preferably treated with at least one of a silane coupling agent and a disilazane compound other than the treating agent.

The silane coupling agent other than the surface treatment agent of the present invention described above is a compound in which a hydrolyzable group (a group capable of forming a silanol group by hydrolysis) and a functional group are bonded to the central silicon atom, and methyltrimethoxysilane , methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltri Alkylalkoxysilane compounds such as ethoxysilane; Polymerizable double bond group-containing alkoxysilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane and p-styryltrimethoxysilane (not including (meth)acryloyl groups);2- (3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyl Epoxy group-containing alkoxysilanes such as triethoxysilane; halogenated alkylalkoxysilane compounds such as 3-chloropropylmethyldimethoxysilane and 3-chloropropyltrimethoxysilane; 3-mercaptopropyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane Mercapto group-containing alkoxysilane compounds such as; 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltri Amino group-containing alkoxysilane compounds such as ethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane; 3-isocyanatopropyltriethoxysilane isocyanate group-containing alkoxysilane compounds such as; fluorinated alkylalkoxysilane compounds such as trifluoropropyltrimethoxysilane; arylalkoxysilane compounds such as phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane and diphenyldiethoxysilane; -methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyl Alkoxysilane compounds having one (meth)acryloyl group such as methyldimethoxysilane; methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, methylvinyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, methyldiphenylchlorosilane, etc. Acyloxysilane compounds such as tetraacetoxysilane, methyltriacetoxysilane, phenyltriacetoxysilane, dimethyldiacetoxysilane, diphenyldiacetoxysilane, trimethylacetoxysilane; dimethylsilanediol, diphenylsilanediol, trimethylsilanol, etc. silanol compounds; and the like.

The disilazane compound means a compound having a Si--N--Si bond in the molecule. Examples of the disilazane compound include 1,1,1,3,3,3-hexamethyldisilazane, 1,1,3,3-tetramethyldisilazane, 1,3-bis(3,3,3-trifluoro propyl)-1,1,3,3-tetramethyldisilazane, 1,3-bis(chloromethyl)tetramethyldisilazane, 1,3-diphenyltetramethyldisilazane, 1,3-divinyl-1,1, 3,3-tetramethyldisilazane, 2,2,4,4,6,6-hexamethylcyclotrisilazane, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane, heptamethyldisilazane silazane, octamethylcyclotetrasilazane, lithium hexamethyldisilazane, sodium hexamethyldisilazane, potassium hexamethyldisilazane, and the like.

Next, a method for producing silica particles (before surface treatment) and a method for producing surface-treated silica particles by surface-treating the silica particles using at least one of the surface treatment agents A and B will be described.

The silica particles of the present invention are produced by hydrolytically condensing an alkoxysilane in the presence of a basic catalyst and an aromatic heterocyclic compound having a nitrogen atom (hereinafter referred to as a "nitrogen-containing aromatic heterocyclic compound"). be able to. Alkoxysilane is hydrolytically condensed in the presence of a basic catalyst, and at this time, silicon atoms contained in alkoxysilane are converted from OH ^- derived from the basic catalyst and OSi ^- derived from hydrolytic condensates of other alkoxysilanes. Under nucleophilic attack, the reaction is believed to proceed by a mechanism similar to the S _N 2 reaction (GJ Brinker, et al., "SOL-GEL SCIENCE", 1990, ACADEMIC PRESS LIMITED, p116-139). . As this hydrolytic condensation progresses, more and more highly electrophilic hydroxy groups, SiO— groups, etc. are bonded to the central silicon atom of the alkoxysilane, and the central silicon atom becomes more susceptible to nucleophilic attack, resulting in hydrolysis. Usually, the decomposition and condensation proceed more easily. However, in the present invention, by interacting with the coexisting nitrogen-containing aromatic heterocyclic compound and the hydrogen atom of the hydroxy group, the reactivity of the central silicon atom is lowered, the hydrolytic condensation is moderated, and the particle size is reduced. It is considered that silica particles with suppressed agglomeration can be obtained in both cases. Silica particles obtained by hydrolytic condensation of alkoxysilane usually have a larger amount of silanol groups on the silica particle surface than silica particles produced by the water glass method disclosed in Patent Document 1 above.

The alkoxysilane is a compound having an alkoxy group as a substituent of the silicon atom, and as a substituent of the silicon atom, in addition to the alkoxy group, an alkyl group having 2 to 6 carbon atoms, or an aromatic group having 6 to 10 carbon atoms. may have a group hydrocarbon group. Moreover, the hydrogen atom of the alkyl group may be substituted with a halogen atom, a vinyl group, a glycidyl group, a mercapto group, an amino group, or the like.

Examples of tetrafunctional alkoxysilanes having only alkoxy groups as silicon atom substituents include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, and dimethoxydiethoxysilane. Alkoxysilanes having an alkoxy group and an unsubstituted alkyl group as substituents on the silicon atom include trifunctional alkoxysilanes such as methyltrimethoxysilane and methyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane and the like. bifunctional alkoxysilanes; monofunctional alkoxysilanes such as trimethylmethoxysilane and trimethylethoxysilane; and the like. Furthermore, alkoxysilanes having an alkoxy group and a substituted alkyl group as substituents on the silicon atom include alkoxysilanes containing chloroalkyl groups such as 3-chloropropylmethyldimethoxysilane and 3-chloropropyltrimethoxysilane; vinyltrimethoxysilane; , vinyl group-containing alkoxysilanes such as vinyltriethoxysilane; aromatic group-containing alkoxysilanes such as phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane; 3-glycidoxypropyltrimethoxysilane, glycidyl group-containing alkoxysilanes such as 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane; mercapto group-containing alkoxysilanes such as 3-mercaptopropyltrimethoxysilane; 3-aminopropyltrimethoxysilane , amino group-containing alkoxysilanes such as 3-(2-aminoethylamino)propyltrimethoxysilane; and the like.

Among them, mono- to tetra-functional alkoxysilanes are preferred, tri- to tetra-functional alkoxysilanes are more preferred, and tetra-functional alkoxysilanes are even more preferred. The larger the functional number (the number of alkoxy groups) of the alkoxysilane, the less likely it is that impurities will be mixed into the fired silica body to be obtained. Of the alkoxysilanes used for fired silica, the content of tetrafunctional alkoxysilane (preferably tetramethoxysilane, tetraethoxysilane) is preferably 90% by mass or more, more preferably 95% by mass or more, and still more preferably 98% by mass. % or more, and the upper limit is 100% by mass. From the viewpoint of reactivity, the alkoxy group preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 to 2 carbon atoms. That is, alkoxysilanes particularly preferably used for the silica particles of the present invention are tetramethoxysilane and tetraethoxysilane.

The concentration of alkoxysilane in the reaction solution for hydrolyzing/condensing alkoxysilane is preferably 0.05 mmol/g or more, more preferably 0.1 mmol/g or more, and the upper limit is not particularly limited. It is preferably 3 mmol/g or less. When the concentration of the alkoxysilane in the reaction solution is within this range, the reaction rate can be easily controlled and the particle size can be made uniform.

Further, the concentration of water in the reaction solution is preferably 2 mmol/g to 25 mmol/g. However, since the amount of water changes due to hydrolysis/condensation of alkoxysilane, the amount at the time of preparation (before the start of hydrolysis/condensation) is used as a standard. The molar ratio of water to alkoxysilane (water/alkoxysilane) is preferably 3-20, more preferably 4-10. When the molar ratio of water to alkoxysilane is within this range, silanol groups remaining inside the silica particles are likely to be reduced.

Examples of the basic catalyst include ammonias, amines, quaternary ammonium compounds, and the like. Examples of the ammonia include ammonia; an ammonia generating agent such as urea; and the like. Examples of the amines include aliphatic amines such as methylamine, ethylamine, propylamine, n-butylamine, dimethylamine, dibutylamine, trimethylamine and tributylamine; alicyclic amines such as cyclohexylamine; aromatics such as benzylamine. group amines; alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; Moreover, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, etc. are mentioned as said quaternary ammonium compound.

Among them, ammonias and amines are preferable from the viewpoint of easy control of the particle size. From the viewpoint of increasing the purity of silica particles to be obtained, the catalyst is preferably a catalyst that can be easily removed from silica. Specifically, ammonias and amines are preferred, and ammonia and aliphatic amines are more preferred. Ammonias are preferred, and ammonia is particularly preferred, from the viewpoint of having both a catalytic effect and ease of removal.

The concentration of the basic catalyst in the reaction solution is preferably 0.8 mmol/g to 2 mmol/g. Further, the total mass ratio of the basic catalyst, basic catalyst and water (basic catalyst/(basic catalyst + water)) is preferably 0.1 or more, more preferably 0.2 or more. and is preferably 0.4 or less, more preferably 0.32 or less.

As the nitrogen-containing aromatic heterocyclic compound, an aromatic heterocyclic compound having a nitrogen atom on the ring is preferable. For example, monocyclic or polycyclic compounds having one nitrogen atom such as pyridine and quinoline; bipyridine and imidazole. monocyclic or polycyclic compounds having two or more nitrogen atoms such as; Only one kind of the nitrogen-containing aromatic heterocyclic compound may be used, or two or more kinds thereof may be used. It is particularly preferable to use at least one of pyridine and imidazole as the nitrogen-containing aromatic heterocyclic compound.

The concentration of the nitrogen-containing aromatic heterocyclic compound in the reaction solution is preferably 0.01 mmol/g to 1 mmol/g. Further, the mass ratio of the nitrogen-containing aromatic heterocyclic compound to the basic catalyst (nitrogen-containing aromatic heterocyclic compound/basic catalyst) is preferably 0.01 or more, more preferably 0.02 or more. It is preferably 0.5 or less, more preferably 0.3 or less.

When hydrolyzing/condensing the alkoxysilane, a diluent may be used together. By containing a diluent, the hydrophobic alkoxysilane and water can be easily mixed, and the degree of progress of hydrolysis and condensation of the alkoxysilane can be made uniform in the reaction solution, and the silica particles obtained. Improves dispersibility. The diluent is preferably a water-soluble organic solvent, and the water-soluble organic solvent is preferably an alcohol solvent, and monools such as methanol, ethanol, propanol, isopropyl alcohol, n-butyl alcohol, t-butyl alcohol, and pentyl alcohol; ethylene glycol, propylene glycol, diols such as 1,4-butanediol; and the like, and alcohols are preferred.

The diluent in the reaction solution is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 55% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass. % by mass or less, more preferably 65% by mass or less.
Further, the diluent is preferably 120 parts by mass or more, more preferably 150 parts by mass or more, still more preferably 180 parts by mass or more with respect to a total of 100 parts by mass of alkoxysilane and water, and 500 parts by mass. or less, more preferably 300 parts by mass or less, and even more preferably 250 parts by mass or less.
The more the diluent, the more likely it is that the progress of the reaction will be uniform, and the less the diluent, the faster the reaction rate. However, since the amount of alcohol changes due to hydrolysis/condensation of the alkoxysilane, the amount of the diluent is based on the amount at the time of preparation (before the start of hydrolysis/condensation).

The reaction solution contains ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; paraffins such as isooctane and cyclohexane; ethers such as dioxane and diethyl ether; A hydrophobic organic solvent may be included. When using these hydrophobic organic solvents, a surfactant may be added to improve dispersibility.

Each of the above components may be mixed in an appropriate order, but for example, at least a portion of each of the above components (e.g., water, basic catalyst, nitrogen-containing aromatic heterocyclic compound, diluent, etc.) is premixed. After preparing the pre-mixture, it may be mixed with the alkoxysilane. The alkoxysilane may be premixed with the diluent and then mixed with the premix.

When hydrolyzing/condensing the alkoxysilane, the reaction temperature is preferably 0 to 100.degree. C., more preferably 20 to 70.degree. C., and even more preferably 20 to 50.degree. The duration of hydrolysis/condensation is preferably 30 minutes to 100 hours, more preferably 1 to 20 hours, even more preferably 2 to 10 hours.

The surface-treated silica particles of the present invention can be produced by adding at least one of the surface treatment agents A and B to the reaction solution after hydrolysis/condensation of the alkoxysilane. In other words, the surface silica particles of the present invention have a d _BET calculated from the specific surface area by the BET method of 1 nm or more and 100 nm or less, and an average secondary particle diameter d _DLS measured by a dynamic light scattering method, It can be produced by surface-treating silica particles having a d _BET ratio (d _DLS /d _BET ) of 1.2 or less with at least one of the surface treatment agents A and B.

The total amount of the surface treatment agents A and B is, for example, 3 to 12 parts by mass, preferably 4 to 10 parts by mass, with respect to 100 parts by mass of the reaction liquid after hydrolysis/condensation of the alkoxysilane, More preferably, it is 5 to 8 parts by mass.

The surface-treated silica particles of the present invention are further surface-treated with at least one of a disilazane compound, a titanium coupling agent, and a silane coupling agent other than the surface-treating agents described above, in addition to the surface-treating agents A and B described above. In such a case, it may be added together with the surface treatment agents A and B to the reaction solution after hydrolysis/condensation of the alkoxysilane.

A surface-treated silica particle dispersion containing the surface-treated silica particles of the present invention and a solvent (hereinafter sometimes referred to as "dispersion solvent") is also included in the technical scope of the present invention. In the surface-treated silica particle dispersion, the surface-treated silica particles are preferably dispersed in a dispersion solvent. The surface-treated silica particle dispersion of the present invention has good uniformity.

The concentration of the surface-treated silica particles is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 7% by mass or more, and preferably 40% by mass or less in 100% by mass of the surface-treated silica particle dispersion. , more preferably 30% by mass or less.

The dispersion solvent can be selected from water; alcohol solvents; ether solvents; ketone solvents; hydrocarbon solvents; halogenated hydrocarbon solvents; Alcohol-based solvents and ketone-based solvents are preferable as the dispersion solvent.

Examples of the alcohol solvent include methanol, ethanol, propanol, 2-propanol, butanol, 2-butanol, isobutyl alcohol, pentanol, methylbutanol, neopentyl alcohol, isopentyl alcohol, hexanol, 2-hexanol, heptanol, 2- monool solvents such as heptanol, octanol, 2-octanol, cyclohexanol, and methylcyclohexanol; diol solvents such as ethanediol, propanediol, butanediol, pentanediol, methylpentanediol, and ethylpentanediol; glycerin, hexanetriol Triol-based solvents such as; Monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, tetraethylene glycol, polyethylene glycol, methoxypropanol (propylene glycol monomethyl ether), ethoxypropanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tri Ether alcohol solvents such as propylene glycol monomethyl ether and polypropylene glycol; Halogenated alcohol solvents such as chloroethanol, chloropropanediol and trifluoroethanol; Hydroxypropionitrile; Aminoethanol, dimethylaminoethanol, diethylaminoethanol, diethanolamine, N- aminoalcohol solvents such as butyldiethanolamine and triethanolamine; and the like.

Examples of the ether solvent include aliphatic hydrocarbon ether solvents such as diethyl ether, dipropyl ether, diisopropyl ether and dibutyl ether; butylphenyl ether, pentylphenyl ether, methoxytoluene, benzylethyl ether, diphenyl ether, dibenzyl ether cyclic ether solvents such as propylene oxide, furan, tetrahydrofuran; 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl polyether solvents such as ether, diethylene glycol dibutyl ether, glycerin ether; and the like.

Examples of the ketone solvent include acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2-heptanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, and acetophenone.

Examples of the hydrocarbon solvent include saturated aliphatic hydrocarbon solvents such as hexane, heptane, and octane; aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, mesitylene, naphthalene, cyclohexylbenzene, and diethylbenzene; and cyclopentane. , saturated alicyclic hydrocarbon solvents such as methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane; and the like.

Examples of the halogenated hydrocarbon solvent include chlorinated aliphatic hydrocarbon solvents such as methyl chloride, dichloromethane, chloroform, carbon tetrachloride, and ethyl chloride; halogenated aromatic hydrocarbons such as chlorobenzene, fluorobenzene, and hexafluorobenzene. system solvent; and the like.

Examples of the ester solvent include formate solvents such as methyl formate, ethyl formate, propyl formate, butyl formate, isobutyl formate, and pentyl formate; methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, 3-methoxybutyl Acetate, sec-hexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, benzyl acetate, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-phenoxyethyl acetate, ethylene glycol Acetate solvents such as monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, methyl acetoacetate, ethyl acetoacetate, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid; propionic acid Propynoic acid ester solvents such as methyl, ethyl propionate, butyl propionate, and isopentyl propionate; γ-butyrolactone: ethylene glycol monoacetate; ethylene diacetate; ethylene glycol ester; diethylene glycol monoacetate; diethyl carbonate, ethylene carbonate, propylene carbonate Carbonic acid ester such as; Lactic acid ester such as ethyl lactate;

The surface-treated silica particle dispersion may be produced by dispersing the surface-treated silica particles in a dispersion solvent, or by replacing the solvent in the reaction solution when preparing the silica particles with the dispersion solvent. may be manufactured. In the case of solvent replacement, by adding a dispersion solvent while filtering the silica particle dispersion before or after the surface treatment with an ultrafiltration membrane, the basic catalyst and nitrogen-containing aromatic used in preparing the silica particles are removed. Group heterocyclic compounds and the like can be removed. Solvent replacement is preferably performed after the surface treatment of the silica particles.

That is, as a method for producing a surface-treated silica particle dispersion, an alkoxysilane is hydrolyzed in the presence of water, a basic catalyst, and an aromatic heterocyclic compound having a nitrogen atom to hydrolyze and condense the alkoxysilane. A method of filtering the subsequent reaction solution with an ultrafiltration membrane can be mentioned. After adding the surface treatment agent to the reaction solution after hydrolysis/condensation, it is preferable to filter with an ultrafiltration membrane. In the production method, a dispersion medium (e.g., water or alcoholic solvent) different from the dispersion medium (reaction solvent) of the reaction solution may be added while filtering through an ultrafiltration membrane. A silica particle dispersion in which silica particles are dispersed in a solvent different from the reaction solvent can be obtained. The silica particle dispersion after ultrafiltration is further treated with a cation exchange resin, and a solvent different from the solvent of the silica particle dispersion (e.g., ether solvent, ketone solvent, hydrocarbon solvent, halogenated hydrocarbon It is preferable to replace with at least one solvent selected from solvent-based solvents, phenol-based solvents and ester-based solvents). By doing so, for example, a silica particle dispersion in which silica particles are dispersed in at least one selected from ether solvents, ketone solvents, hydrocarbon solvents, halogenated hydrocarbon solvents, phenol solvents and ester solvents can be manufactured. In the treatment with the cation exchange resin described above, the basic catalyst and the like adsorbed on the particle surface can be removed. The substitution with the ether-based solvent or the like may be performed by partially or completely replacing the solvent of the silica particle dispersion. The solvent of the silica particle dispersion to be substituted is preferably removed by solid-liquid separation means such as centrifugation or solvent distillation.

Conventionally known cation exchange resins can be used, and either weakly acidic cation exchange resins or strongly acidic cation exchange resins may be used. Examples of weakly acidic cation exchange resins include Amberlite IRC-76 (manufactured by Organo Corporation), Diaion WK10, WK20 (manufactured by Mitsubishi Chemical Corporation), Lewatit CNP80 (manufactured by Bayer KK), and the like. . Examples of strongly acidic cation exchange resins include Amberlyst 16, Amberlite IR-120B (manufactured by Organo Corporation), Diaion PK-208, PK-228, PK-216 (manufactured by Mitsubishi Chemical), and Duolite C. -26, Duolite ES-26 (manufactured by Sumitomo Chemical), MSC-1, 88 (manufactured by Dow) and the like.

The technical scope of the present invention also includes a surface-treated silica particle-containing resin composition containing the surface-treated silica particles of the present invention and a polymerizable monomer.

The concentration of the surface-treated silica particles is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 7% by mass or more, and preferably 70% by mass in 100% by mass of the resin composition containing surface silica particles. Below, it is more preferably 50% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

As the polymerizable monomer, one or more may be used, and examples thereof include monofunctional monomers and crosslinkable monomers.
The monofunctional monomer is a polymerizable carbon-carbon double bond as long as it is a compound having one, can be used one or two or more, (meth) acrylic acid ester; styrene, p- styrenic monomers such as tert-butylstyrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, p-chlorostyrene, p-chloromethylstyrene; carboxy group-containing monomers such as (meth)acrylic acid; Examples include hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 3-hydroxy-2-hydroxypropyl (meth)acrylate, and 3-phenoxy-2-hydroxypropyl (meth)acrylate. Specific examples of the above (meth)acrylic acid esters include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth) (Meth)acrylic acid alkyl esters such as acrylates, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; (meth)acrylic acid cycloalkyl esters such as cyclohexyl (meth)acrylate;2 ,4-dibromo-6-sec-butylphenyl (meth)acrylate, 2,4-dibromo-6-isopropylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,6-tribromophenyl (meth)acrylate , Pentabromophenyl (meth) acrylate and other (meth) acrylic acid aryl esters; benzyl (meth) acrylate, pentabromobenzyl (meth) acrylate and other (meth) acrylic acid aralkyl esters; phenoxyethyl (meth) acrylate, phenoxy- 2-methylethyl (meth)acrylate, 2,4,6-tribromophenoxyethyl (meth)acrylate, 2,4-dibromophenoxyethyl (meth)acrylate, 2-bromophenoxyethyl (meth)acrylate, 1-naphthyloxy Ethyl (meth)acrylate, 2-naphthyloxyethyl (meth)acrylate, phenoxy-2-methylethyl (meth)acrylate, phenoxyethoxyethyl (meth)acrylate having an aryloxy unit (meth)acrylic acid ester; phenylthio (meth)acrylic acid esters having an arylthiooxy group such as ethyl (meth)acrylate, 1-naphthylthioethyl (meth)acrylate, 2-naphthylthioethyl (meth)acrylate; methoxypolyethylene glycol (meth)acrylate, phenoxypolyethylene Alkylene glycol mono(meth)acrylates such as glycol (meth)acrylate; (meth)acrylic acid esters having a glycidyl group such as glycidyl (meth)acrylate;

The crosslinkable monomer may be any compound containing a plurality of carbon-carbon double bonds. As the crosslinkable monomer, one or two or more can be used, and examples thereof include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di( meth)acrylate, 1,6-hexanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tetramethylene glycol di(meth)acrylate Alkylene glycol poly(meth)acrylates such as; neopentyl glycol poly(meth)acrylates such as neopentyl glycol di(meth)acrylate, dineopentyl glycol di(meth)acrylate; trimethylolpropane tri(meth)acrylate, ethoxylated (3) trimethylolpropane tri(meth)acrylate, propoxylation (3) trimethylolpropane tri(meth)acrylate, epoxidation (3) trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, etc. trimethylolpropane poly(meth)acrylate; glyceryl poly(meth)acrylate such as glyceryl tri(meth)acrylate, ethoxylated glyceryl tri(meth)acrylate; pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxy Polyfunctional ( meth) acrylates; polyfunctional styrene monomers such as divinylbenzene; diallyl phthalate, diallyl isophthalate, triallyl cyanurate, triallyl isocyanurate and other polyfunctional allyl ester monomers; Ethoxy) ethyl (meth) acrylate; urethane acrylate oligomer (e.g., Shiko (registered trademark) series (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), CN series (manufactured by Sartomer), Unidic (registered trademark) series (DIC Corporation ), KAYARAD (registered trademark) UX series (manufactured by Nippon Kayaku Co., Ltd.), etc.);

The content of the polymerizable monomer is preferably 1 part by mass or more, more preferably 10 parts by mass or more, still more preferably 50 parts by mass or more, and preferably 500 parts by mass with respect to 100 parts by mass of the surface-treated silica particles. parts or less, more preferably 300 parts by mass or less, and even more preferably 150 parts by mass or less.

The surface-treated silica particle-containing resin composition of the present invention may further contain a polymerization initiator. Examples of polymerization initiators include photopolymerization initiators and thermal polymerization initiators, which may be used alone or in combination. Some photopolymerization initiators act as thermal polymerization initiators, and some thermal polymerization initiators act as photopolymerization initiators. It is possible to cure the active energy ray-curable aqueous resin composition. Among the polymerization initiators, photopolymerization initiators are preferable because they do not impart heat history to the formed film, the base material to which the active energy ray-curable aqueous resin composition is applied, and the like.

Examples of thermal polymerization initiators include 2,2'-azobis-(2-methylbutyronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis-(2,4'- dimethylvaleronitrile), benzoyl peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butylperoxy-2-ethylhexanoate and other oil-soluble initiators, Persulfates such as potassium persulfate, ammonium persulfate and sodium persulfate; water-soluble peroxides such as hydrogen peroxide; water-soluble azo compounds such as 2,2'-azobis(2-amidinopropane) dihydrochloride; However, the present invention is not limited only to such examples. These thermal polymerization initiators may be used alone or in combination of two or more.

Examples of photopolymerization initiators include benzophenone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, oxyphenyl-acetic acid 2-[ 2-oxo-2-phenylacetoxyethoxy]-ethyl ester, oxyphenyl acetic acid 2-[2-hydroxyethoxy]-ethyl ester, 1-hydroxycyclohexylphenyl ketone, 2,4,6-trimethylbenzoyl-diphenyl-phos Fin oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)2-hydroxy-2 -methylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]2-morpholinopropan-1-one, 2-morpholinopropan-1-one, iodonium, sulfonium salt, diazonium salt, (4 -methylphenyl[4-(2-methylpropyl)phenyl])-hexafluorophosphate, diethylthioxanthone, isopropylthioxanthone, etc., but the present invention is not limited to these examples. These photopolymerization initiators may be used alone, respectively, or two or more of them may be used in combination.

The amount of the polymerization initiator is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, still more preferably 2 parts by mass or more, and preferably 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer. parts or less, more preferably 10 parts by mass or less.

The surface-treated silica particle-containing resin composition may contain a solvent, if necessary. Examples of the solvent contained in the silica particle-containing resin composition include the same solvent as the dispersion solvent. The content of the solvent is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, still more preferably 100 parts by mass or more, and preferably 2000 parts by mass or less, with respect to 100 parts by mass of the surface-treated silica particles. It is preferably 1000 parts by mass or less.

The surface-treated silica particle-containing resin composition can be produced by mixing the surface-treated silica particle dispersion and a polymerizable monomer. Solvent may be removed if desired.

A cured product (for example, a cured coating film) of the silica particle-containing resin composition is also included in the technical scope of the present invention.

The pencil hardness of the cured product measured by the method shown in the examples below is preferably 2H or more, more preferably 3H or more, and still more preferably 4H or more, and the upper limit is not limited, but for example 7H. .

The total light transmittance of the cured product is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, and may be 99% or less. The total light transmittance of the cured coating film can be determined according to JIS K7361-1 using a turbidimeter (NDH-5000, manufactured by Nippon Denshoku Industries Co., Ltd.).

The haze of the cured product is preferably 1.5% or less, more preferably 1.3% or less, still more preferably 1.0% or less, still more preferably 0.90% or less, and the lower limit is Although not particularly limited, it may be 0.3%, for example. The haze of the cured product can be determined according to JIS K7136:2000 using a turbidimeter (NDH-5000, manufactured by Nippon Denshoku Industries Co., Ltd.).

The thickness of the cured product is preferably 0.1 µm or more, more preferably 1 µm or more, still more preferably 2 µm or more, and preferably 20 µm or less, more preferably 10 µm or less, still more preferably 7 µm or less.

The cured product can be produced by applying a silica particle-containing resin composition onto a substrate or a film and curing the composition. When the silica particle-containing resin composition contains a polymerizable monomer and a polymerization initiator, it may be cured by heat or light (ultraviolet) irradiation.

The surface-treated silica particles of the present invention are suitably used for coating materials for hard coats.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by the following examples, and it is of course possible to make appropriate modifications within the scope that can be adapted to the gist of the above and below. Included in scope.

Silica particles and silica particle-containing resin compositions obtained in Examples and Comparative Examples below were evaluated by the following methods.

[Measurement of BET method average particle diameter (BET diameter) of silica particles before surface treatment]
After vacuum-drying the resulting silica particles at 110° C., the specific surface area of the silica particles was measured by the BET method using a Macsorb 1210 fully automatic gas adsorption measuring device manufactured by Mountech. The BET diameter was obtained based on the following formula. The density of silica was 2.2 g/cm ³ .
d _BET (μm)=6/(specific surface area of silica particles measured by BET method (m ² /g)×density of silica (g/cm ³ ))

[Measurement of average particle diameter (DLS diameter) based on dynamic light scattering method of silica particles before surface treatment]
The particle diameter measured with a concentrated particle size analyzer (manufactured by Otsuka Electronics Co., Ltd., FPAR1000, laser light wavelength 650 nm) is shown as the DLS diameter. A silica particle dispersion (9% silica particle dispersion in methanol) was used as a sample for measurement by the dynamic light scattering method.

[Measurement of average particle size and coefficient of variation]
An arbitrarily collected surface-treated silica particle dispersion was observed using a transmission electron microscope at a measurement magnification at which the number of silica particles contained in one field of view was about 100 to 300, and five or more fields of view were obtained. In the transmission electron microscope image, the primary particle diameters of all the particles contained in the electron microscope image were measured to obtain an average value, and the average particle diameter of the primary particles of the surface-treated silica particles was obtained. The major diameter of each particle was defined as the primary particle diameter of each particle. Also, the standard deviation of the primary particle size was determined, and the coefficient of variation (%) was determined based on the following formula.
Variation coefficient (%) = (standard deviation of primary particle size / average particle size of primary particles) x 100

[Measurement of sphericity]
The arbitrarily collected surface-treated silica particle dispersion was observed using a transmission electron microscope at a measurement magnification at which the number of silica particles contained in one field of view was about 50 to 100, and the transmission of 5 or more fields of view obtained. In the electron microscope image, the short diameter and long diameter of all particles contained in the electron microscope image are measured, and the sphericity of each particle is obtained by dividing the short diameter by the long diameter, and the average sphericity of all particles is obtained. was calculated.

[Measurement of total light transmittance and haze]
Both the total light transmittance and the haze were measured using a turbidity meter (NDH-5000, manufactured by Nippon Denshoku Industries Co., Ltd.). The total light transmittance was determined according to JIS K7361-1, and the haze was determined according to JIS K7136:2000.

[Pencil hardness test]
The pencil hardness of the surface of the cured coating film was measured according to JIS K5600. The specific procedure is as follows. Scrape off only the wooden part of the pencil, leaving a cylindrical core of 5-6 mm. After that, the tip of the core is flattened with abrasive paper. Each time the test is performed, the tip of the wick is flattened with abrasive paper. A pencil is set in a testing machine specified by JIS. When the tester is in a horizontal position, the tip of the pencil is placed at 45±1° and a load of 750±10 g against the cured coating. After placing the tip of the pencil on the surface of the cured coating film, the tester is moved by 7 mm or more at a moving speed of 0.5 to 1 mm/s while maintaining the above load. The test is performed with increasing hardness of the pencil while changing the test area until a scar of at least 3 mm or more is produced. The hardness of the hardest pencil that did not leave a scar is taken as the pencil hardness in this test.

[Scratch resistance test]
The surface of the cured coating film was rubbed with #0000 steel wool 10 times at a load of 1500 g/cm ² , and the scratch resistance was evaluated according to the following criteria according to the number of scratches. The test was performed with a stroke length of 5 cm and a speed of 1 reciprocation/second.
○: No scratches when visually observed △: 1 to 3 scratches when visually observed ×: 4 or more scratches when visually observed

Synthesis example 1
To 10.6 g of pentaerythritol tetraacrylate (A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.), 5.9 g of 3-mercaptopropyltrimethoxysilane (KBM-803, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and 0.15 g of triethylamine (Wako Pure Chemical Industries, Ltd.) was added. was added and allowed to react at room temperature for 5 hours to prepare a surface treatment agent A1 represented by the following formula.

Synthesis example 2
To 28.9 g of dipentaerythritol hexaacrylate (A-DPH manufactured by Shin-Nakamura Chemical Co., Ltd.), 9.8 g of 3-mercaptopropyltrimethoxysilane (KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and 0.25 g of triethylamine (Wako Pure Pharmaceutical Co., Ltd.) was added and allowed to react at room temperature for 5 hours to prepare a surface treatment agent A2 represented by the following formula.

Production example 1
step (a)
8120 g of methanol, 1426 g of water, 846 g of 25% aqueous ammonia, and 90 g of pyridine were added to a 20 L SUS container equipped with a stirrer, a dropping port, and a thermometer, and stirred for 30 minutes to obtain a homogeneous solution. While the solution was adjusted to 49 to 51° C. and stirred, 2840 g of tetramethylorthosilicate (TMOS) was added dropwise from the dropping port over 1 hour. After completion of dropping, hydrolysis was continued for 1 hour to obtain an alcoholic solution dispersion (1) of silica particles. The obtained dispersion (1) was again heated to 50° C., and 900 g of the surface treatment agent A1, 205 g of hexyltrimethoxysilane (KBM-3063 manufactured by Shin-Etsu Chemical Co., Ltd.), hexamethyldisilazane (Shin-Etsu Chemical Co., Ltd. 50 g of industrial SZ-31) was added dropwise from the dropping port over 6 hours. After completion of dropping, aging was continued for 1 hour to obtain an alcoholic solution dispersion (2) of acrylic group-containing hydrophobic silica particles.

The BET diameter (d _BET ) of the silica particles obtained in the alcoholic solution dispersion (1) (that is, the silica particles before surface treatment) was 11.8 nm, and the DLS diameter (d _DLS ) was 12.6 nm. and the ratio of d _DLS to the d _BET (d _DLS /d _BET ) was 1.07.

step (b)
Dispersion (2) obtained in step (a) is filtered at room temperature using a commercially available ultrafiltration membrane equipped with a ceramic tubular ultrafiltration membrane having a cutoff molecular weight of about 10,000 while adding methanol as appropriate. , solvent replacement, and concentration to a SiO ₂ concentration of about 11% to obtain a methanol dispersion (3) of acrylic group-containing hydrophobic silica particles.

step (c)
The obtained silica particle methanol dispersion (3) is passed through a column filled with a hydrogen-type strongly acidic cation exchange resin Amberlite IR-120B (manufactured by Organo) under room temperature conditions at a space velocity of 3 per hour. A methanol dispersion (4) of acidic acryl group-containing hydrophobic particles was obtained by passing through at a high speed and filtering through a 3 μm PTFE membrane filter. 800 g of propylene glycol monomethyl ether (PGM) was successively added to 1800 g of the obtained dispersion (4) while concentrating it by distillation under reduced pressure using a rotary evaporator to replace the _solvent . % to obtain a PGM dispersion (5) of acrylic group-containing hydrophobic silica particles.

Production example 2
The same treatment as in steps (a) and (b) of Production Example 1 is performed except that 900 g of surface treatment agent A1 added in step (a) of Production Example 1 is changed to 1250 g of surface treatment agent A2, A methanol dispersion (6) of acrylic group-containing hydrophobic silica particles was obtained.

The acrylic group-containing hydrophobic silica particle methanol dispersion (6) was subjected to the same treatment as in the step (c) of Production Example 1 to obtain a PGM dispersion of acrylic group-containing hydrophobic silica particles (7). .

Production example 3
The same treatment as in steps (a) and (b) of Production Example 1, except that 385 g of 3-acryloxypropyltrimethoxysilane was used instead of 900 g of surface treatment agent A1 added in step (a) of Production Example 1. was carried out to obtain a methanol dispersion (8) of acrylic group-containing hydrophobic silica particles.

The methanol dispersion (8) of the acrylic group-containing hydrophobic silica particles was subjected to the same treatment as in the step (c) of Production Example 1 to obtain a PGM dispersion (9) of the acrylic group-containing hydrophobic silica particles. rice field.

Example 1
In a brown glass bottle, 6.7 g of PGM dispersion (5) of acrylic group-containing hydrophobic silica particles synthesized in Production Example 1, 2.0 g of dipentaerythritol hexaacrylate (KAYARD DPHA manufactured by Nippon Kayaku), propylene glycol 11.3 g of monomethyl ether and 0.06 g of Irgacure 184 (photoradical polymerization initiator, manufactured by Ciba Japan) were charged, and the resulting silica particle-containing composition was placed on a PET film (Toyobo Cosmosine A4300 film thickness 100 μm). , the film was coated with a bar coater so as to have a film thickness of 5 μm, dried at 80° C. for 10 minutes, and cured by irradiating ultraviolet rays of 500 mJ/cm ² with a high-pressure mercury lamp to obtain a cured coating film.

Example 2
The procedure of Example 1 was repeated except that the PGM dispersion of acrylic group-containing hydrophobic silica particles (7) synthesized in Production Example 2 was used instead of the PGM dispersion of acrylic group-containing hydrophobic silica particles (5). to obtain a cured coating film.

Comparative example 1
The procedure of Example 1 was repeated except that the PGM dispersion of acrylic group-containing hydrophobic silica particles (9) synthesized in Production Example 3 was used instead of the PGM dispersion of acrylic group-containing hydrophobic silica particles (5). to obtain a cured coating film.

Comparative example 2
Silica particle dispersion MIBK solution (Nissan MIBK-ST manufactured by Kagaku Kogyo Co., Ltd.) is added, and after stirring at room temperature, a mixture of methyl ethyl ketone and water is added and stirred overnight at room temperature to obtain silica particles modified with a polyfunctional acrylate monomer modification modifier. An attempt was made to prepare a reaction solution containing However, since the solution gelled, a resin composition containing silica particles and a monomer could not be produced.

Various physical properties of the obtained cured coating film are shown in Table 1 below. Further, the thickness of the cured coating films in Examples 1 and 2 and Comparative Examples 1 and 2 were all 5 μm. The coefficient of variation and sphericity described in the column of Comparative Example 2 are values measured with silica particles before surface treatment.

According to Table 1, in Examples 1 and 2, the silica particles surface-treated with the surface treatment agent specified in the present invention have the coefficient of variation of the primary particle size and the sphericity in the range specified in the present invention. The scratch resistance of the film is good. On the other hand, in Comparative Example 1 using monofunctional 3-acryloxypropyltrimethoxysilane as the surface treatment agent, the scratch resistance of the cured coating film was inferior.

Claims (5)

Silica particles surface-treated with a surface treatment agent,
The surface treatment agent includes (i) a silane coupling agent having a thiol group, a thioMichael addition reaction product of a trifunctional or higher (meth)acrylate monomer, and (ii) a silane coupling agent having an isocyanate group, At least one selected from the group consisting of a bond with a bifunctional or higher (meth)acrylate monomer having one or more hydroxy groups,
The coefficient of variation of the primary particle size measured with a transmission electron microscope is 20% or less,
sphericity is 0.90 or more,
Surface-treated silica particles having an average primary particle size of 5 to 50 nm as measured by a transmission electron microscope . The (i) silane coupling agent having a thiol group and a thioMichael addition reaction product with a trifunctional or higher (meth)acrylate monomer are represented by the following formula (A), and the (ii) silane cup having an isocyanate group 2. The surface-treated silica particles according to claim 1, wherein a compound of a ring agent and a bifunctional or more functional (meth)acrylate monomer having one or more hydroxy groups is represented by the following formula (B).

(In formula (A), n is an integer of 1 to 3, m is an integer of 1 to 10, X ¹ is an alkoxy group having 1 to 4 carbon atoms, R ¹¹ is an alkyl group having 1 to 4 carbon atoms, R ¹² is a group represented by the following formula (1A).)

(In the above formula (1A), p is an integer of 2 to 10, and A ¹ is a linear, branched or cyclic (p+1)-valent hydrocarbon group having 1 to 30 carbon atoms or the hydrocarbon group Part of the methylene chain of -O-, -NH-C(=O)-, -C(=O)-NH-, -OC(=O)-, -C(=O)O- a substituted organic linking group, and R ^a1 is independently a hydrogen atom or a methyl group.)

(wherein t is an integer of 1 to 3, s is an integer of 1 to 10, X ² is an alkoxy group having 1 to 4 carbon atoms, R ²¹ is an alkyl group having 1 to 4 carbon atoms, R ²² is a group represented by the following formula (1B).)

(In the formula (1B), q is an integer of 2 to 5, B ¹ is a linear, branched or cyclic (q+1)-valent hydrocarbon group having 1 to 10 carbon atoms or methylene of the hydrocarbon group Part of the chain is substituted with -O-, -NH-C(=O)-, -C(=O)-NH-, -OC(=O)-, -C(=O)O- is an organic linking group, and R ^b1 is independently a hydrogen atom or a methyl group.) A surface-treated silica particle dispersion comprising the surface-treated silica particles according to claim 1 or 2 and a solvent. A surface-treated silica particle-containing resin composition comprising the surface-treated silica particles according to claim 1 or 2 and a polymerizable monomer. A cured product of the surface-treated silica particle-containing resin composition according to claim 4 .